DRAWING SPIRAL STAIRCASE USING SOLID EDGE ST3

[davincigee]

Hi,
I need to draw a vertical storage tank with domed roof on Solid Edge ST3. My main challenge is the drawing of the spiral staircase around the tank. Can anyone please help me out?

 

[kjoiner]

Hello,

I think I can help out somewhat with this. Here are the major steps to take:

1. Get a spiral curve wrapped around the tank. To do this, you need need to create a sketch in the front plane (assuming it's the center of the tank). Draw a vertcial line from the bottom of the tank to the top. Then draw a horizontal line from the center of the top of the tank to some distance out from the radius of the tank. Then, using the surfacing tools, create a swept surface using the vertical line as the path and the horizontal line as the profile. Also notice while you're in the dialogue box, there is a section called "twist". You can't do anything yet, but once the surface is created, you can go back and define the twist which will be how many times you want to go around the tank. Once you get this to work, you will have a purple surface that looks like a giant auger. Then use the intersection command to create a line where the surface meets the tank. This will create a sprial line wrapped around the tank.

2. Create a stair tread sticking out from the tank. Using the top plane, draw a line from the center of the tank to the edge. If you know how wide your tread will be, you can extend the line that much beyond the surface of the tank. One tricky part I have not gone into is knowing where the first tread will be off the ground, marking that point on the sprial line and then drawing your line through that point. You can probably do that by drawing an extruded surface from top to bottom using that radial line I just mentioned. The goal is to get a stair tread that is perpendicular to the surface of the tank at the point on the sprial line where the first tread will be from the ground. When you create the stair tread, you can make a plane normal to the radial line out from the tank surface. Create a tread profile and then extrude it back to the surface of the tank.

3. Pattern the stair tread along the sprial line. Use the pattern along curve command. You can pick how many treads you want and you'll probably have to play with it to meet the standards for tread rise. One the stairs are patterned, they probably won't look right. You need to go to the advanced definition step and pick "full from surface" for the first option and then "curve position" for the rotation type.

By the way, I have to give credit for step 1 to someone on the Solid Edge forum who demonstrated a way to make a "loxodrome" curve in which he did pretty much what I did in step one except he wrapped it around a sphere instead of a cylinder. I used that method as an example and put it on a cylinder.

I hope this helps. By the way I'm running ST4 so the same tools should be available in ST3.

Kyle